LITHOLOGICAL FEATURES AND ORGANIC MATTER OF SEDIMENTS IN THE SOUTH-EASTERN LAPTEV SEA (MUOSTAKH CAPE)

Abstract

The present study seeks to improve current understanding of modern climate changes, which are considered as the consequences of the greenhouse effect caused by increasing content of the main greenhouse gases – carbon dioxide and methane. Complex studies in the land–shelf–atmosphere system across the Arctic shelf, including biogeochemical and lithological analyses of sediments across Eastern Arctic seas, are needed. The research aims to study both lithological and mineralogical sediment compositions, variability of the organic matter content (Corg), molecular and isotopic composition of carbon (δ13C) contained in the ice complex deposits (ICD) along the Laptev Sea coast (Cape Muostakh). Samples of modern bottom sediments obtained during the expedition of 2015 in the south-eastern part of the Laptev Sea were investigated. Methods used in the present study include GC-MS analysis, pyrolysis, isotope analysis, X-ray phase analysis followed by further numerical processing and interpretation. Results. The mineralogical composition of the clay fraction has been studied, and the distribution of clay minerals has been established. The features of molecular and isotopic Corg composition are revealed. Initial results on the hydrocarbon source of ICD- Corg, which dominates in the shallow part of the East Siberian Arctic shelf, are obtained. Pyrolysis and GC-MS data are highly correlated reflecting complex biogeochemical processes occurring during the Corg transformation at the various stages of lithogenesis. In addition, the study provides preliminary estimates of the light hydrocarbons generation potential for the Corg contained in the sediments.

Keywords

• organic matter
• bottom sediments
• isotope analysis
• gc-ms
• mineralogical composition
• laptev sea
• cape muostakh